1. Field of the Invention
The present invention relates generally to a hydraulic seed clutch actuator for seed drills of the type used to plant seeds in agricultural operations. The term "seed drill" is intended herein to encompass various types of seed planters including traditional seed drills, row planters and other similar devices. More particularly, the invention relates to such a hydraulic seed clutch actuator which is linked to an OEM hydraulic lifting system on the seed drill. The inventive hydraulic actuator assures that, when an operator, typically a person driving a tractor towing the seed drill, operates a hydraulic control to lift the seed drill, as at the end of a planted row, the seed clutch is simultaneously operated to immediately cut off seed metering.
2. Description of the Related Art
A variety of seed drills are typically used in modern large scale agricultural crop planting operations. A typical seed drill includes a frame upon which one or more seed hoppers are positioned. The seed hopper(s) have a plurality of seed discharge openings, each of which feeds into a respective seed metering devices. The seed metering devices are typically linked via a common drive shaft which is powered from a linkage connected to ground engaging wheels on the seed drill. Seed metering rate is thus proportional to the ground speed of the seed drill. One or more seeds from the metering mechanisms are dropped into respective seed tubes with each few inches of travel, which dropped seeds are fed through the seed tubes and dropped into a furrow opened by a single or pair of furrowing discs. A tamping wheel and/or a closing wheel typically follow the disc(s) and the seed tube to tamp the seed into the furrow and then to close the furrow, respectively.
Considerable research goes into the development of improved strains of crops, many of which are patented by research institutions and seed companies. Many of these improved crops exhibit a variety of improved characteristics, including increased yield and greater resistance to pests and disease. However, the costs of these improved seeds is also considerably higher than that of conventional seed. Farmers are thus faced with tough decisions on whether to risk the extra cost for improved seed as a trade-off for the expectation or hope for better crop yields. As seed prices continue to escalate, the importance of conserving seed becomes ever more important.
In a conventional seed drill with which the present invention is concerned, a farmer will typically operate a hydraulically driven rocker arm which pivots to raise and lower the furrowing discs as the tractor and seed drill reach the end of each series of planted rows and resume the next series of rows, respectively. A mechanically operated seed clutch is attached to a linkage which links the seed clutch to the rocker arm. As the rocker arm pivots to lift the seed drill, the connected linkage disengages the seed clutch to isolate the seed metering drive shaft from a drive shaft driven by ground engaging wheels on the seed drill. The seed clutch is thus responsive to the raising of the seed drill to shut off power to the seed metering shaft, and to thus stop dispensing seed after the drill is lifted. The tractor and towed seed drill are then turned 180 degrees and the seed drill is lowered to start another series of planted rows.
A problem with this approach to actuating a seed clutch is an inherent delay in operation of the seed clutch due to the linkage operation. Typically, the seed clutch is not disengaged until the seed drill is near the fully raised position, and is reengaged as the seed drill is starting to lower. This means that seed continues to be metered out and dropped through the seed tubes as the drill is being lifted, and then again as the seed drill is being lowered. Depending upon the travel speed of the tractor, seed can be dropped on the ground for as long as six feet or more each time the seed drill is raised and lowered. Taking an average 40 acre field to be planted, and assuming a square shape and a seed drill width of 15 feet, a tractor would make 88 passes across the field during planting. With each pass, seed is dispensed past the planted row for an average distance of 6 feet, and ahead of the next row series for an additional 6 feet. Multiplying 12 feet times 88 passes means that 1056 feet of seed can be wasted in that field. Of course, if the field is irregularly shaped or includes terraces, the seed drill will need to be raised more often, which can increase the seed wastage. The problem of wasted seed is particularly costly in soy bean or corn plantings, but is a problem no matter what crop is being planted.
It is clear, then, that a need exists for an apparatus which quickly and positively shuts off and resumes seed metering in a seed drill under the control of an operator. Such an apparatus should be a convenient and economical retrofit for existing seed drills, and should be readily operable from existing tractor hydraulics and controls.